Rotary mill



May 29, 1928.

J. IHLEFELDT ROTARY MILL Filed Aug. 51. 1926 al/w oa fa M58 06 1,. mA/for/zeg.

Patented May 29, 1928.

' UNITED STATES PATENT OFFICE.

JOHANNES IHLEI'ELDT, OEDESSAU, GERMANY, ASSIGNOR TO THE FIRM G.POLYSIUS,

OF DESSAU, GERMANY.

Bump MILL.

Application filed August 81, messes 110. 132,742 and in GermanySeptember 1, '1925.

My invention relates to an improved rotary mill provided with aplurality of chainbers and working with intermediate sifting. Moreespecially, the invention resides there: in, that hearing ledges areprovided in the sitting chambers :located between the individualgrinding cl'iambers, said ledges serving for the reception of individualsieves; another feature resides therein that said sieves are attached tothe said ledges by means of screws, bolts or the like. In order torender possible removing the sieves from the outside a plurality of theholding means mentioned is arranged in apertures, such as slots or thelike, provided inthe closing covers of the mill, the arrangen'ient beingsuch that two sieves may be drawn out through a feed aperture after therespective cover with its bolt has been removed.

The invention is illustrated diagrammatically andby'wayof example on theaccompanying drawing on which 7 Fig.- 1 is a cross section through themill, and

Fig. ber.

The sifting chamber C which is located between two grinding chambers Aand B carries on the inner'surface ofthe walls a plurality of stationaryledges (1 formed, for instance, by pieces of angle iron or the like,their number corresponding with that of the 2 a section through'thesifting chamsieves There are provided, in the example shown, eightsieves f in the sifting-chamber C of the mill, and arranged practicallyside The sieves form in this example by side. obtuse angles, the sittingchambels being, therefore, polygonal, but the shape of the sieves may besuch that a sitting chamber of circular section is obtained. The sievesf are retained in proper position by the ledges (Z of a suitablesection, as well as by screw bolts 9, the heads h of which press therims of the sieves 7' upon said ledges kl, as shown in the figures. Eachsieve is supported by two ledges. Some of the bolts 9 are connectedwith, and carried by, a covercl'osing an aperture is and being affixedto the mlll casmg by screws or the like. When the screw or the like hasbeen removed, the JKSPGCtlVB cover i can be removed from the respectiveaperture and the adjacent sieve or sieves may be removed from the mill.

, Owing to the particular construction of the mill, as shown anddescribed, one holding device is required for two sieves, but, on theother hand, only four apertures are required for removing eight sievesfrom out of the mill. The other bolts, that is to say, those locatedbetween the apertures need only be screwed oil the ledgesd, when thesieves can be withdrawm also from the intermediate ledges cooperatingwith the just mentioned bolts.

Fig. 1 shows how a sieve f is just being removed from the drum, and alsothe neighbouring sieve f may be removed instantly thereafter in the samemanner.

I claim:

A multi-chamber mill comprising grinding compartments and anintermediate sifting compartment, said sitting compartment beingprovided with a series of circularly arranged ledges, sitter sectionsseated upon said ledges, clamping devices operative from the exterior ofthe mill wall for holding the sections uponsaid ledges, the mill wall ofsaid sitter compartment being provided with openings one for each pairof sitter sections through which each pair of sections may be removedfrom the mill and closure means for said openings.

In testimonywhereof I atiix my signature.

J OHANNES IHLEFELDT.

